Influence of slope on the dissolved pollutant transport process over impervious surface

Disso lved pollutants are an important pa rt o f urban rainfall r unoff po llut ion. T o r eveal their t ranspo rt pro cess during the rainfall r uno ff stage is of gr eat sig nificance to urban wastew ater t reatment. I n this study, w e conducted a series o f ex peri2 ments to study the pro cesses of r ainfall- runoff and dissolved pollutant tr ansport o ver imper vio us surface at different slopes ( 01 5b, 1b, 2b, 3b, 4b, 5b) . The results show ed that the hig her the surface slope, the sho rter the time of runoff yield and concentr a2 tion, and t he faster it to ok fo r the runoff volume to reach stability. T he po llutant concentr ation would decrease as the ra infall runo ff depth increased; the hig her the slope, the higher the initial concent ratio n, and t he faster the attenuation. T he pollutant transpo rt r ate wo uld incr ease first and then decrease with time; the hig her the slope, the larg er the peak o f pollutant transpo rt rate. T he peak of pollutant transpo rt r ate appeared when the cumulative runoff depth was 01 3 to 01 5 mm. T he pollutant trans2 port process co nfo rmed to the ex po nential wash2off model. The wash2off coefficient k w ould increase linearly f irst and then re2 main basically stable w hen the slo pe was abov e 3b. Com par ed w ith particulate po llutants, the disso lv ed po llutants had a lar ger was2off coefficient and wer e more likely to be washed o ff, especially in the initia l r unoff stag e.

Project Supported:

Clc Number: